Extremophiles: A Powerful Choice for Bioremediation of Toxic Oxyanions

By having toxic effects on human health, oxyanion contamination in wastewater is considered a priority among environmental concerns to be resolved. Widespread applications of the oxyanions in various industries and metal mining activities in certain environments resulted in high concentrations of these materials especially effluent in their toxic forms. One of the acceptable methods considered by a number of researchers to reduce their toxicity is bioreduction of oxyanions by microorganisms which is considered as one of the bioremediation methods. However, the major problem for bioremediation by conventional methods is the extreme conditions of industrial effluents, such as high salinity, high or low pH, and high temperature. Nature itself has given the solution to this problem, i.e., extremophiles, microorganisms that survive in these harsh conditions. Due to their ability in reducing metalloids and detoxifying them, they are suitable candidates for biological treatments. Here, the efficacy of various extremophile groups in bioremediation of major oxyanions including arsenic, selenium, chromium, and tellurium is reviewed.